1. Field of The Invention
The present invention relates generally to an apparatus for attenuating pressure pulsations in a hydraulic system. More particularly, the present invention relates to a tube muffler for air conditioning system of an automotive vehicle which attenuates the pressure pulsations propagated from the compressor of the air conditioning system.
2. Disclosure Information
Automotive heating, ventilating and air conditioning systems are known to be an annoying source of noise in a vehicle's passenger compartment. There are two components in the HVAC system that generate the majority of the noise: the air conditioning compressor in the refrigeration system and the blower in the air distribution system. The air conditioning compressor can produce a variety of steady state intransient noises depending on the ambient conditions, the type of compressor: (piston, rotary or scroll), number of cylinders in the engine and the associated drive ratio, and different engine operating conditions. The majority of the objectionable noise produced by the compressor results from the acoustical wave propagation of the air conditioning refrigerant through the air conditioning hoses in the engine compartment. These pulsations are readily transmitted through the various components in the air conditioning system, such as the evaporator or accumulator to become audible in the vehicle interior.
The prior practice in compressor noise reduction has been to test a variety of packageable, standard expansion chamber-type mufflers and evaluate/optimize them by trial and error to determine an acceptable configuration. This type of design and tuning process becomes very irrational, expensive, and can result in mufflers tuned to the wrong frequencies. Therefore, it would be advantageous to provide an air conditioning muffler which could be used to tune an automotive air conditioning compressor operating at a variety of wave propagation frequencies with minimal amounts of trial and error to determine optimal configurations.